In the field of broadcasting, in particular of radio broadcasting, programs, commonly referred to as “transmissions”, are sent from a transmitter to a plurality of receiver terminals.
Thus radio programs, television programs, and interactive programs allow access to auxiliary programs such as video, audio, or interactive programs in the context of broadcasting main programs.
Methods of managing auxiliary programs are known in the art that aim to enable an auxiliary program to be used subsequently to its broadcast window, in particular from the published international application WO-01/50763-A1.
The above document describes in detail a method of managing an analog stream, but makes no reference to how to manage a plurality of auxiliary programs broadcast with main programs in a digital data stream.
In the context of digital applications, auxiliary programs and main programs are multiplexed and transmitted in the same digital data stream.
All the main and auxiliary programs are transmitted in sections in a cyclic sequence that is repeated continuously, the various portions of the programs being time-division multiplexed. Transmission of this kind is commonly referred as “carrousel transmission” or “carousel transmission.”
In response to a request to access a given program, the receiver locks onto one of the digital data streams from a plurality of streams that form the transmission.
During a first cycle of listening to the carrousel transmission, the receiver detects data identifying programs and in particular a required auxiliary program.
Using this identification data, during a second cycle of listening to the digital data stream, the receiver extracts all the constituent elements of the required auxiliary program in order to reconstruct it and to execute it either immediately or subsequently.
The details of such transmission are known in the art and are set out in particular in the specification ISO 13818.6, which is part 6 of the standard defining MPEG-2 coding.
However, the above management method gives rise to the problem that the receiver must wait for a plurality of transmission cycles, i.e. turns of the carrousel, in order to be able to reconstitute the whole of the auxiliary program required by the user, which waiting time makes the system less user-friendly and in particular less interactive.
Accordingly, there is at present no method of managing auxiliary programs broadcast with main programs in a digital data stream that enables rapid execution of an auxiliary program required by a user.